// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_ELEMENTS_H_
#define V8_ELEMENTS_H_

#include "src/elements-kind.h"
#include "src/keys.h"
#include "src/objects.h"

namespace v8 {
namespace internal {

    class JSTypedArray;

    // Abstract base class for handles that can operate on objects with differing
    // ElementsKinds.
    class ElementsAccessor {
    public:
        explicit ElementsAccessor(const char* name)
            : name_(name)
        {
        }
        virtual ~ElementsAccessor() = default;

        const char* name() const { return name_; }

        // Returns a shared ElementsAccessor for the specified ElementsKind.
        static ElementsAccessor* ForKind(ElementsKind elements_kind)
        {
            DCHECK_LT(static_cast<int>(elements_kind), kElementsKindCount);
            return elements_accessors_[elements_kind];
        }

        // Checks the elements of an object for consistency, asserting when a problem
        // is found.
        virtual void Validate(JSObject obj) = 0;

        // Returns true if a holder contains an element with the specified index
        // without iterating up the prototype chain.  The caller can optionally pass
        // in the backing store to use for the check, which must be compatible with
        // the ElementsKind of the ElementsAccessor. If backing_store is nullptr, the
        // holder->elements() is used as the backing store. If a |filter| is
        // specified the PropertyAttributes of the element at the given index
        // are compared to the given |filter|. If they match/overlap the given
        // index is ignored. Note that only Dictionary elements have custom
        // PropertyAttributes associated, hence the |filter| argument is ignored for
        // all but DICTIONARY_ELEMENTS and SLOW_SLOPPY_ARGUMENTS_ELEMENTS.
        virtual bool HasElement(JSObject holder, uint32_t index,
            FixedArrayBase backing_store,
            PropertyFilter filter = ALL_PROPERTIES)
            = 0;

        inline bool HasElement(JSObject holder, uint32_t index,
            PropertyFilter filter = ALL_PROPERTIES);

        // Note: this is currently not implemented for string wrapper and
        // typed array elements.
        virtual bool HasEntry(JSObject holder, uint32_t entry) = 0;

        // TODO(cbruni): HasEntry and Get should not be exposed publicly with the
        // entry parameter.
        virtual Handle<Object> Get(Handle<JSObject> holder, uint32_t entry) = 0;

        virtual bool HasAccessors(JSObject holder) = 0;
        virtual uint32_t NumberOfElements(JSObject holder) = 0;

        // Modifies the length data property as specified for JSArrays and resizes the
        // underlying backing store accordingly. The method honors the semantics of
        // changing array sizes as defined in EcmaScript 5.1 15.4.5.2, i.e. array that
        // have non-deletable elements can only be shrunk to the size of highest
        // element that is non-deletable.
        virtual void SetLength(Handle<JSArray> holder, uint32_t new_length) = 0;

        // If kCopyToEnd is specified as the copy_size to CopyElements, it copies all
        // of elements from source after source_start to the destination array.
        static const int kCopyToEnd = -1;
        // If kCopyToEndAndInitializeToHole is specified as the copy_size to
        // CopyElements, it copies all of elements from source after source_start to
        // destination array, padding any remaining uninitialized elements in the
        // destination array with the hole.
        static const int kCopyToEndAndInitializeToHole = -2;

        // Copy all indices that have elements from |object| into the given
        // KeyAccumulator. For Dictionary-based element-kinds we filter out elements
        // whose PropertyAttribute match |filter|.
        virtual void CollectElementIndices(Handle<JSObject> object,
            Handle<FixedArrayBase> backing_store,
            KeyAccumulator* keys)
            = 0;

        inline void CollectElementIndices(Handle<JSObject> object,
            KeyAccumulator* keys);

        virtual Maybe<bool> CollectValuesOrEntries(
            Isolate* isolate, Handle<JSObject> object,
            Handle<FixedArray> values_or_entries, bool get_entries, int* nof_items,
            PropertyFilter filter = ALL_PROPERTIES)
            = 0;

        virtual MaybeHandle<FixedArray> PrependElementIndices(
            Handle<JSObject> object, Handle<FixedArrayBase> backing_store,
            Handle<FixedArray> keys, GetKeysConversion convert,
            PropertyFilter filter = ALL_PROPERTIES)
            = 0;

        inline MaybeHandle<FixedArray> PrependElementIndices(
            Handle<JSObject> object, Handle<FixedArray> keys,
            GetKeysConversion convert, PropertyFilter filter = ALL_PROPERTIES);

        virtual void AddElementsToKeyAccumulator(Handle<JSObject> receiver,
            KeyAccumulator* accumulator,
            AddKeyConversion convert)
            = 0;

        virtual void TransitionElementsKind(Handle<JSObject> object,
            Handle<Map> map)
            = 0;
        virtual void GrowCapacityAndConvert(Handle<JSObject> object,
            uint32_t capacity)
            = 0;
        // Unlike GrowCapacityAndConvert do not attempt to convert the backing store
        // and simply return false in this case.
        virtual bool GrowCapacity(Handle<JSObject> object, uint32_t index) = 0;

        static void InitializeOncePerProcess();
        static void TearDown();

        virtual void Set(Handle<JSObject> holder, uint32_t entry, Object value) = 0;

        virtual void Add(Handle<JSObject> object, uint32_t index,
            Handle<Object> value, PropertyAttributes attributes,
            uint32_t new_capacity)
            = 0;

        static Handle<JSArray> Concat(Isolate* isolate, Arguments* args,
            uint32_t concat_size, uint32_t result_length);

        virtual uint32_t Push(Handle<JSArray> receiver, Arguments* args,
            uint32_t push_size)
            = 0;

        virtual uint32_t Unshift(Handle<JSArray> receiver, Arguments* args,
            uint32_t unshift_size)
            = 0;

        virtual Handle<JSObject> Slice(Handle<JSObject> receiver, uint32_t start,
            uint32_t end)
            = 0;

        virtual Handle<Object> Pop(Handle<JSArray> receiver) = 0;

        virtual Handle<Object> Shift(Handle<JSArray> receiver) = 0;

        virtual Handle<NumberDictionary> Normalize(Handle<JSObject> object) = 0;

        virtual uint32_t GetCapacity(JSObject holder,
            FixedArrayBase backing_store)
            = 0;

        virtual Object Fill(Handle<JSObject> receiver, Handle<Object> obj_value,
            uint32_t start, uint32_t end)
            = 0;

        // Check an Object's own elements for an element (using SameValueZero
        // semantics)
        virtual Maybe<bool> IncludesValue(Isolate* isolate, Handle<JSObject> receiver,
            Handle<Object> value, uint32_t start,
            uint32_t length)
            = 0;

        // Check an Object's own elements for the index of an element (using SameValue
        // semantics)
        virtual Maybe<int64_t> IndexOfValue(Isolate* isolate,
            Handle<JSObject> receiver,
            Handle<Object> value, uint32_t start,
            uint32_t length)
            = 0;

        virtual Maybe<int64_t> LastIndexOfValue(Handle<JSObject> receiver,
            Handle<Object> value,
            uint32_t start)
            = 0;

        virtual void Reverse(JSObject receiver) = 0;

        virtual void CopyElements(Isolate* isolate, Handle<FixedArrayBase> source,
            ElementsKind source_kind,
            Handle<FixedArrayBase> destination, int size)
            = 0;

        virtual Object CopyElements(Handle<Object> source,
            Handle<JSObject> destination, size_t length,
            uint32_t offset = 0)
            = 0;

        virtual Handle<FixedArray> CreateListFromArrayLike(Isolate* isolate,
            Handle<JSObject> object,
            uint32_t length)
            = 0;

        virtual void CopyTypedArrayElementsSlice(JSTypedArray source,
            JSTypedArray destination,
            size_t start, size_t end)
            = 0;

    protected:
        friend class LookupIterator;

        // Element handlers distinguish between entries and indices when they
        // manipulate elements. Entries refer to elements in terms of their location
        // in the underlying storage's backing store representation, and are between 0
        // and GetCapacity. Indices refer to elements in terms of the value that would
        // be specified in JavaScript to access the element. In most implementations,
        // indices are equivalent to entries. In the NumberDictionary
        // ElementsAccessor, entries are mapped to an index using the KeyAt method on
        // the NumberDictionary.
        virtual uint32_t GetEntryForIndex(Isolate* isolate, JSObject holder,
            FixedArrayBase backing_store,
            uint32_t index)
            = 0;

        virtual PropertyDetails GetDetails(JSObject holder, uint32_t entry) = 0;
        virtual void Reconfigure(Handle<JSObject> object,
            Handle<FixedArrayBase> backing_store, uint32_t entry,
            Handle<Object> value,
            PropertyAttributes attributes)
            = 0;

        // Deletes an element in an object.
        virtual void Delete(Handle<JSObject> holder, uint32_t entry) = 0;

        // NOTE: this method violates the handlified function signature convention:
        // raw pointer parameter |source_holder| in the function that allocates.
        // This is done intentionally to avoid ArrayConcat() builtin performance
        // degradation.
        virtual void CopyElements(JSObject source_holder, uint32_t source_start,
            ElementsKind source_kind,
            Handle<FixedArrayBase> destination,
            uint32_t destination_start, int copy_size)
            = 0;

    private:
        static ElementsAccessor** elements_accessors_;
        const char* name_;

        DISALLOW_COPY_AND_ASSIGN(ElementsAccessor);
    };

    void CheckArrayAbuse(Handle<JSObject> obj, const char* op, uint32_t index,
        bool allow_appending = false);

    V8_WARN_UNUSED_RESULT MaybeHandle<Object> ArrayConstructInitializeElements(
        Handle<JSArray> array, Arguments* args);

    // Called directly from CSA.
    // {raw_context}: Context pointer.
    // {raw_source}: JSArray pointer.
    // {raw_destination}: JSTypedArray pointer.
    void CopyFastNumberJSArrayElementsToTypedArray(Address raw_context,
        Address raw_source,
        Address raw_destination,
        uintptr_t length,
        uintptr_t offset);
    // {raw_source}, {raw_destination}: JSTypedArray pointers.
    void CopyTypedArrayElementsToTypedArray(Address raw_source,
        Address raw_destination,
        uintptr_t length, uintptr_t offset);
    // {raw_source}, {raw_destination}: JSTypedArray pointers.
    void CopyTypedArrayElementsSlice(Address raw_source, Address raw_destination,
        uintptr_t start, uintptr_t end);

} // namespace internal
} // namespace v8

#endif // V8_ELEMENTS_H_
